Method and device for the detection of SF6 decomposition products

Abstract

This invention is in the field of gas detection for sulphur hexafluoride (SF6) gas decomposition products, particularly for the detection of thionyl fluoride (SOF2) and sulphur dioxide (SO2). The invention relates to a novel portable handheld instrument that can readily detect SOF2, SF4 and SO2 in SF6 gas filled electrical equipment and in air. An apparatus for detecting SF6 decomposition products comprising: (a) an inlet for receiving SF6 gas containing SOF2 or SF4; (b) A chamber connected to the inlet and containing a catalyst which converts SOF2 or SF4 into SO2; and (c) an SO2 detector connected downstream of the chamber.

Description

REFERENCE TO RELATED APPLICATION [0001] This application claims the benefit of the filing date of U.S. provisional application Ser. No. 60 / 561,910, filed 14 Apr. 2004.FIELD OF THE INVENTION [0002] This invention is in the field of gas detection for sulphur hexafluoride (SF6) gas decomposition products, particularly for the detection of thionyl fluoride (SOF2), sulphur tetrafluoride (SF4) and sulphur dioxide (SO2). The invention relates to a novel portable handheld instrument that can readily detect SOF2, SF4 and SO2 in SF6 gas filled electrical equipment, and in air. BACKGROUND OF THE INVENTION [0003] Sulphur hexafluoride (SF6) is a colorless, odorless, non-toxic and non-flammable gas. It has good dielectric and arc-quenching characteristics. These unique properties have made it a popular choice as a dielectric medium for high voltage equipment. Since its introduction in the 1950's, its popularity has grown to include circuit breakers, switches, current transformers, busbars, and ca...

AI Technical Summary

Benefits of technology

[0029] The process can include a flow control which can regulate the rate of flow of the SF6 gas.

Problems solved by technology

Even these more stable gases will eventually further react with moisture or metal oxides and may lead to corrosion of the equipment.

In addition, many of these gases are highly toxic and pose a health issue to personnel performing maintenance, servicing or cleanup of the equipment.

SF6 decomposition products have a distinct acrid odour similar to that of rotten eggs but due to their toxic nature, this method of detection is discouraged.

The forewarning of the decomposition products anticipates costly breakdowns.

This method is not selective since some metallic deposits may also produce a change in resonant frequency of the crystal.

In addition, this is also a wet method that could be very messy to implement.

The sensor lowers its resistance when exposed to decomposition products.

However, the equipment is costly and the interpretation of the results is not simple.

The measurement is not in real time and is not very accurate.

This process is manual and the results are subject to operator errors.

Depending on the distance of the lab from the equipment, the delay could be weeks.

Because of sample degradation, and potential for contamination during sampling, the results of the analysis may be inaccurate and usually lower than actual.

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